1. Field of the Invention
The present invention relates to a printed-circuit board with conductive circuit patterns formed thereon for electric connections to electronic parts.
2. Description of the Related Art
FIG. 5 depicts a conventional printed-circuit board 100 on which there are merely formed electrically isolated conductive circuit patterns 101.
On the other hand, since tin and lead in solder have a harmful effect on the human body and cause environmental destruction when the printed-circuit boards are disposed of, a jack 103 is used to provide electric connections by pressure contact without the use of the solder.
As shown in FIGS. 5 through 7, the jack 103 has an insulating housing 105, a cylindrical portion 107 formed integrally therewith and having a plug insertion hole 106, and terminals 104 partly projecting down through the bottom of the insulating housing 105, the projecting portions being bent so that they are resiliently deformable in the vertical direction in FIG. 5.
The jack 103 has its insulating housing 105 fixed to a case of equipment (not shown). By fixing the printed-circuit board 100 to the case, the terminals 104 are pressed against the conductive circuit patterns 101 of the board 100 to establish electric connections therebetween.
With such a printed-circuit board 100, electric signals from a plug (not shown) inserted in the plug insertion hole 106 are applied via the terminals 104 to the conductive circuit patterns 101, through which they are provided to other electric parts (not shown) connected to the patterns 101. Alternatively, electric signals transmitted through the conductive circuit patterns 101 are fed to the plug received in the plug insertion hole 106.
Since the connection between the terminals 104 of the jack 103 and the conductive circuit patterns 101 depends on the pressure contact, not the soldering, what is called fretting (or chafing) corrosion is caused by vibrations or shocks. That is, the conductive circuit patterns 101 are ablated by the terminals 104 to form metal powder, which shorts the electrically isolated conductive circuit patterns 101, causing electronic parts associated therewith to malfunctions or damage to them.
It is therefore an object of the present invention to provide a printed-circuit board which ensures preventing malfunctions of electronic parts and damage thereto.
The printed-circuit board according to the present invention is characterized in that desired conductive circuit patterns formed thereon are separated by protection or partition walls higher than the circuit patterns.
With terminals of electronic parts connected to the conductive circuit patterns, electric signals from the former are applied to the latter and vice versa.
In the event that metal powder results from fretting corrosion, it is prevented by the protective walls from shorting the conductive circuit patterns.